let s = Symbol();// 独一无二
let s2 = Symbol();
let obj = {
    a:1,
    [Symbol()]:function(arg) {
        console.log('---')
    },
    [Symbol()]:function(arg) {
        console.log('+++')
    }
}
for(let key in obj){
    console.log(key,111);
}
Object.getOwnPropertySymbols(obj)
.forEach(item=>{
    obj[item]();
})
console.log(Object.keys(obj));
console.log(Object.getOwnPropertyNames(obj),1);
console.log(Object.getOwnPropertyDescriptors(obj,[Symbol()]))
console.log(Object.getOwnPropertySymbols(obj),2);
obj.a
obj[s]
//console.log(obj[s]())
//console.log(obj)